Nahj al-Balāgha, no. 364

He commanded it to remain stationary in obedience to His commands. He made its sun the bright indication for its day, and moon the gloomy indication for its night. He then put them in motion in their orbits and ordained their (pace of) movement in the stages of their paths in order to distinguish with their help between night and day, and in order that the reckoning of years and calculations may be known by their fixed movements. Then He hung in its vastness its Sky and put therein its decoration consisting of small bright pearls and lamp-like stars. He shot at the over-hearers arrows of bright meteors. He put them in motion on their appointed routine and made them into fixed stars, moving stars, descending stars, ascending stars, ominous stars and lucky stars.